Acetylcholine is a neurotransmitter that induces signal transduction in the central nervous system and the neuromuscular connections (the parasympathetic nerve and motor nerve). In the central nervous system, nuclei of origin of the acetylcholine neuron are in the brain stem and forebrain, and those acetylcholine neurons project to cerebral cortex, hippocampus, and limbic area. In addition, some interneurons in some brain areas such as striatum utilize acetylcholine as a neurotransmitter. Acetylcholine receptor is classified into a ligand dependent ion channel (cholinergic nicotinic receptor) and a G-protein-conjugated receptor (cholinergic muscarinic receptor). The cholinergic muscarinic receptor is one kind of receptor for excitatory neurotransmitter acetylcholine, and was named based on the selective activation of the receptor by muscarine. The muscarinic receptor is further classified into subtypes of M1 to M5, and the M1 receptor is known to be widely distributed mainly in the brain, and deeply involved particularly in learning, memory, sleep, neuropathic pain and the like. The importance of cholinergic muscarinic M1 receptor in brain physiology is well known, and a compound having an M1 receptor function enhancing action is expected to be useful as a prophylactic or therapeutic drug for mental diseases, neurodegenerative diseases, memory disorders, pain, sleep disorders and the like (non-patent document 1).
WO 2006/020879A1 (patent document 1) discloses the following compound as a metabotropic glutamate receptor modulator which is effective for neurological and psychiatric disorder associated with glutamate dysfunction:
wherein each symbol is as defined in the document.
WO 2013/063549A1 (patent document 2) discloses the following compound as a compound effective for neurological and psychiatric disorder associated with muscarinic acetylcholine receptor dysfunction.
wherein each symbol is as defined in the document.
Bioorganic & Medicinal Chemistry Letters, 20 (2010), 1972-1975 (non-patent document 2) discloses the following compound and the like as a M1 receptor positive allosteric modulator:

Gordon, C. P., Byrne, N., McCluskey, A. Green Chem., 2010, 12, 1000-1006. (non-patent document 3) discloses the following compounds similar to the compound of the present invention.

WO 2010/096338A1 (patent document 3) discloses the following compound as an M1 receptor positive allosteric modulator effective for Alzheimer's disease, schizophrenia, pain or sleep disorder.
wherein each symbol is as defined in the document.
WO 95/030647A1 (patent document 4) discloses the following compound similar to the compound of the present invention.
wherein each symbol is as defined in the document.
WO 2007/139464A1 (patent document 5) discloses the following compound as a CB1 receptor ligand effective for pain, cancer, multiple sclerosis, Parkinson's disease, Huntington's chorea, Alzheimer's disease, anxiety disorder, gastrointestinal disorder and cardiovascular disorder.
wherein each symbol is as defined in the document.
US 2008/0108659A1 (patent document 6) discloses the following compound as a compound having a poly(ADP ribose)polymerase (PARP) activity, and useful for cancer, central nervous system disease, inflammatory disease and the like.
wherein each symbol is as defined in the document.
WO 2011/006794A1 (patent document 7) discloses the following compound as a compound which selectively inhibits the activity of poly (ADP-ribose) polymerase PARP-1 with respect to poly (ADP-ribose) polymerase PARP-2 and useful for cancer, cardiovascular diseases, central nervous disorders and the like.
wherein each symbol is as defined in the document.
WO 2012/003147A1 (patent document 8) discloses the following compound as a compound having an M1PAM activity, and effective for Alzheimer's disease, schizophrenia, pain, and sleep disorder.
wherein each symbol is as defined in the document.
WO 2012/158475A1 (patent document 9) discloses the following compound as a compound having an M1PAM activity, and effective for Alzheimer's disease and the like.
wherein each symbol is as defined in the document.
WO 2013/129622A1 (patent document 10) discloses the following compound as a compound having an M1PAM activity, and effective for Alzheimer's disease and the like.
wherein each symbol is as defined in the document.
WO 2015/028483A1 (patent document 11) discloses the following compound as a muscarinic M1 receptor positive allosteric modulator, which is effective for Alzheimer's disease and the like.
wherein each symbol is as defined in the document.
WO 2015/044072A1 (patent document 12) discloses the following compound as a muscarinic M1 receptor positive allosteric modulator, which is effective for Alzheimer's disease and the like.
wherein each symbol is as defined in the document.
WO 2015/049574A1 (patent document 13) discloses the following compound as a muscarinic acetylcholine receptor M1 positive allosteric modulator, which is effective for Alzheimer's disease and the like.
wherein each symbol is as defined in the document.